Editing Nutrition (section)

== Nutrition Across the Lifespan ==

=== Infancy (birth to 12 months) ===

* Energy needs are roughly 100 to 110 kcal/kg/day in early infancy, far higher per kilogram than at any later stage.
* Breast milk or iron-fortified formula is the sole source of nutrition for about the first 6 months. Exclusively and partially breastfed infants receive 400 IU/day of supplemental vitamin D beginning shortly after birth.
* Introduce iron-fortified single-grain cereal and pureed foods around 6 months, when the infant can sit with support, has good head control, and has lost the extrusion reflex. Introduce '''one new food at a time and wait 3 to 5 days''' to identify allergic reactions.
* '''No honey before 12 months''' because of the risk of infant botulism.
* '''No cow's milk before 12 months.''' It causes occult gastrointestinal blood loss, is low in iron, and presents an excessive renal solute load. Whole milk is given from 12 to 24 months for brain development.
* Avoid choking hazards: whole grapes, nuts, popcorn, hot dog rounds, hard candy, raw carrot pieces, and spoonfuls of peanut butter.
* Never prop a bottle or put the infant to bed with a bottle, because of aspiration risk, otitis media, and early childhood caries.
* Expected growth: birth weight doubles by about 6 months and triples by 12 months.

=== Toddler and Preschool ===

* Growth slows and appetite drops. '''Physiologic anorexia''' is normal and reassurance is the intervention.
* Food jags, ritualism, and picky eating are developmentally normal. Offer small portions, roughly 1 tablespoon of each food per year of age, allow self-feeding, avoid using food as reward or punishment, and do not short-order cook.
* Limit milk to about 16 to 24 ounces per day to prevent milk anemia from displacing iron-rich foods.
* Screen for iron deficiency anemia and lead exposure. Adequate iron and calcium intake reduce lead absorption.

=== School Age and Adolescence ===

* Adolescence brings the second-fastest growth period and the highest calorie, protein, calcium, and iron needs of childhood. Menstruating girls need more iron.
* Peak bone mass is built during adolescence, so calcium and vitamin D intake now determines fracture risk decades later. Sugar-sweetened and carbonated beverages displace milk.
* Screen for eating disorders, disordered eating in athletes, and skipped meals.

=== Pregnancy and Lactation ===

* '''Folic acid''' 400 mcg/day for all people capable of pregnancy and 600 mcg/day during pregnancy prevents neural tube defects. The neural tube closes by about day 28, often before pregnancy is recognized, so preconception intake is what matters. People with a prior affected pregnancy require a much higher prescribed dose.
* Calorie needs increase by roughly 340 kcal/day in the second trimester and 450 kcal/day in the third, and by about 450 to 500 kcal/day during lactation. There is no meaningful increase in the first trimester.
* Iron demand roughly doubles; supplementation is routine. Take iron with vitamin C and on an empty stomach if tolerated, and expect dark stools and constipation.
* Recommended total gain for a woman with a normal pre-pregnancy BMI is about 25 to 35 pounds.
* '''Avoid''' alcohol entirely, high-mercury fish (shark, swordfish, king mackerel, tilefish), raw or undercooked fish, meat, and eggs, unpasteurized milk and soft cheeses, unheated deli meats and hot dogs, and raw sprouts, because of listeriosis and toxoplasmosis risk. Limit caffeine to about 200 mg/day.
* Encourage 8 to 12 ounces per week of low-mercury fish such as salmon, sardines, and canned light tuna for omega-3 fatty acids.
* Manage morning sickness with dry crackers before rising, small frequent meals, and separating fluids from solids.

=== Older Adults ===

* Calorie needs fall with reduced lean body mass and activity, but protein, calcium, vitamin D, and vitamin B12 needs stay the same or rise. Nutrient density becomes the priority.
* '''Thirst sensation is blunted''', making dehydration the most common fluid and electrolyte disorder in this population. Offer fluids on a schedule rather than waiting for the patient to ask.
* Atrophic gastritis reduces gastric acid and impairs vitamin B12 absorption from food. Fortified foods or supplements are recommended.
* Barriers to intake include poor dentition and ill-fitting dentures, xerostomia from polypharmacy, diminished taste and smell, dysphagia, depression, social isolation, functional limits on shopping and cooking, and fixed income.
* Sarcopenia responds to adequate protein spread across meals plus resistance activity.
* '''Nursing application:''' Rather than adding salt to make food palatable for a patient on a sodium restriction, use herbs, spices, lemon juice, and vinegar.